The inventor has, in his U.S. Pat. No. 4,219,181 described a device for governing a hydraulic actuator by means of an electrically heated wire (a thermowire), which activates a servo valve controlling the supply of working fluid. Experience has shown that it is difficult rapidly to combine a nominal value signal and an actual value signal into a signal ensuring a suitable heating of the wire. This will cause an undesirable instability at the piston of the actuator, which may have a detrimental influence upon the performance of the actuator.
The aim of the present invention is to propose a governing means, which rapidly and accurately adjusts the position of the piston of the actuator, as described, and which will bring about this adjustment with a low consumption of working fluid.